However, critics said it allowed too many loopholes for ASEAN, which groups a diverse range of political systems ranging from authoritarian regimes in Laos and Vietnam to freewheeling democracies such as the Philippines.

On the day the pact was signed, leaders were having to discuss the ethnic violence in ASEAN member Myanmar, where clashes in Rakhine State between Muslim and Buddhists have left 180 people dead since June.

ASEAN Secretary-General Surin Pitsuwan said yesterday that the violence was disturbing and risked destabilizing the region.

He said leaders would discuss the bloodshed and potentially include a statement referring to it in their end-of-summit communique.

The ASEAN event will be expanded into a two-day East Asia Summit starting today.

US President Barack Obama is due to arrive in Phnom Penh today after making a visit to Myanmar.

Obama decided to go to Myanmar to reward and further encourage political developments by the new reformist government there.

However the Organisation of Islamic Cooperation, which on Saturday described the Muslim Rohingya minority as victims of “genocide,” has urged Obama to pressure Myanmar’s government to stop the bloodshed.

During their summit yesterday, ASEAN leaders forged a united position on negotiating with China over territorial claims to the strategically vital South China Sea.

China insists it has sovereign rights to nearly all of the sea, including waters near the coasts of its Asian neighbors.

ASEAN members Vietnam, the Philippines, Malaysia and Brunei also have claims to the sea, as well as Taiwan.

The rival claims have for decades made the waterways, home to some of the world’s most important shipping lanes and believed to sit atop vast natural resources, a potential military flashpoint.

Tensions escalated this year amid complaints by the Philippines and Vietnam that China was becoming increasingly aggressive in staking its claim to the sea.

After infighting among ASEAN members on how to deal with the issue, Surin said the bloc would propose to Chinese Premier Wen Jiabao (溫家寶) at the East Asia Summit that they quickly begin top-level talks on the issue.

He said ASEAN leaders had agreed on the main negotiating points for China in regards to a long-awaited code of conduct aimed at governing behavior and reducing tensions in the South China Sea.

“On the ASEAN side, [we are] ready, willing and very much committed, but it takes two to tango,” Surin told reporters.

China offered no signs of a change in position as Chinese Ministry of Foreign Affairs spokesman Qin Gang (秦剛) restated Beijing’s preference to deal directly with rival claimants rather than ASEAN as a bloc.

“We are continuing to discuss with ASEAN countries and particularly with those countries related [rival claimants],” he said.